Power generators utilizing, for example, temperature differences between two natural locations such as volcano or naturally heated underground water, or different temperatures at different ocean depths, have been in existence. The present invention utilizes the difference between ambient temperatures at different elevations, the difference between daytime and nighttime temperature, or generally low grade heat sources.
The present invention also utilizes large differences in elevation to obtain an increase in the availability of the energy contained in a working medium. The scale of this invention is large. Column heights of several hundred meters, or even several thousand meters are required to efficiently utilize temperature differentials commonly found in nature. As the scale is large, so is the power output potential. Megawatt outputs would be typical of a practical installation. These considerations are summarized in the following objects:
First, to provide a power generator wherein a pressure resisting closed tubular loop is subjected to ambient temperatures to establish an upper cooled end and a lower heated end joined by a penstock column and a return column, the closed loop containing a fluid under pressure, having a critical temperature between the ambient temperatures at the upper and lower ends, whereby the fluid condenses at the upper end for downward flow in liquid phase through the penstock column and evaporates at the lower end for upward flow in gaseous phase through the return column, the penstock column having one or more generators driven by the downwardly flowing fluid in its liquid phase.
Second, to provide a power generator, as indicated in the preceding object, wherein heat exchangers are disposed at the upper and lower ends of the loop and are of such capacity as to maintain an essentially constant movement of the fluid through variations in ambient temperature.
Third, to provide a power generator, as indicated in the preceding objects, wherein, but not by way of limitation, the lower end is a station disposed in a sun heated valley and the upper end is a station disposed on a mountain top.